Genetics is the study of genes, their expression, genetic differences and heredity in living organisms. Sometimes this difference is suspected to happen because of the absence of a normal component (e.g. one gene). Researchers study the mutated gene and its phenotype and compare it to the so-called 'wild type' or normal phenotype to try to understand how things went wrong.

Although genetics plays a large role in the appearance and behavior of organisms, it is the combination of genetics with what an organism experiences (environment-lifestyle) that determines the ultimate outcome. For example, while genes play a role in determining a person's height, their nutrition and health of that person during childhood may also have a major effect.

Once this molecular component of inheritance was understood, the possibilities for research grew enormously. The field has seen a dramatic shift in the past decade from a pure genetic explanation for cancer to a mixed genetic/epigenetic explanation that has important implications for understanding disease causation, deciphering the pathways affected and devising new strategies for prevention and treatment of cancer.

Molecular Biology

Molecular biology is the study of the molecular pathways in cells. For example, it studies the basics of replication, transcription and translation of genetic material.

The central dogma of molecular biology states that genetic material is transcribed into RNA and then translated into protein. This statement, however, is undergoing revision in light of emerging novel roles for RNA.

The field overlaps with other areas of biology and chemistry, particularly genetics and biochemistry. A large proportion of current cancer researchers consider themselves molecular biologists, which can be viewed as a sub-field of cell biology.

How do we know what we know?

		James D. Watson and Francis Crick determined the structure of DNA in 1953. Although the structure of DNA showed how inheritance worked, it was still not known how DNA influenced the behavior of cells. In the years following, scientists tried to understand how DNA controls the process of protein production. It was discovered that the cell uses DNA as a template to create matching messenger RNA (a molecule with nucleotides, very similar to DNA). The nucleotide sequence of a messenger RNA is used to create an amino acid sequence in protein; this translation between nucleotide and amino acid sequences is known as the genetic code.
Image courtesy of 'To Know Ourselves', The U.S. Department of Energy and the Human Genome Project

Applications of Molecular Biology

The precise functioning of our cell's regulatory systems is essential to maintaining balance and health. When these systems malfunction due to mutations or epigenomic changes, cancer may occur.

Thanks to an ever-increasing knowledge of molecular biology, identification of the exact changes that that cause a cell to become cancerous, provide new targets for cancer therapy. In theory, these targets are cancer cell-specific, thus sparing normal cells from negative anticancer therapy side effects.

Only through continued study and increasing understanding of the abnormal properties that distinguish cancer cells from normal cells can researchers hope to develop truly effective cancer therapies.

Systems Biology

Systems biology reflects a relatively new approach that focuses on the study of complex interactions, as opposed to the more traditional reductionist (single idea - by single idea) approach.

Systems biology is the study of an organism, viewed as an integrated and interacting network of genes, proteins and biochemical reactions, which give rise to life.

Instead of analyzing individual components or aspects of the organism, such as sugar metabolism or a cell nucleus, systems biologists focus on all the components and the interactions among them, all as part of one integrated system.

This approach to science, that pools the talents of mathematicians, engineers and computer scientists as well as biologists, pathologists and cancer specialists, has the potential to lead to a more individualized, and potentially more effective approach to diagnosis and treatment.

 

		If the systems biology approach is successful, and that remains a big "if", it will help researchers to change the way they bring new medicines into development. It is hoped this will reduce the size of clinical trials, the cost of clinical trials, and ensure that doctors prescribe the right medicines for the right patient at the right time.
Image courtesy of University of Stuttgart

Other Disciplines

Contributions from physics, chemistry and bioengineering are often more technical (i.e., developing tools that can be used to study molecular biology) rather than theoretical. Nevertheless, they have led to a rapid acceleration in the understanding of cancer.